money = 5000000

surplus = money

def Surplus():
    global surplus
    print(f'余额：{surplus:.2f}')


def saving():
    balance = float(input('请输入你要存取的金额:'))
    global surplus
    surplus = balance + surplus
    print(f'余额：{surplus:.2f}')


def withdrawal():
    balance = float(input('请输入你要取出的金额:'))
    global surplus
    surplus = surplus - balance
    print(f'余额:{surplus:.2f}')


name = None
name = input("请输入你的名字:")
print(f'欢迎{name}来到银行系统！')
while True:
    # 菜单
    print('----------银行系统-菜单----------')
    print('1.查询余额')
    print('2.存款')
    print('3.取款')
    print('4.退出银行系统')
    print('请输入要进行的操作:')
    choice = int(input())
    if choice == 1:
        Surplus()
    elif choice == 2:
        saving()
    elif choice == 3:
        withdrawal()
    else:
        print('退出系统！')
        break

dict = {1, 2, 3, 4, 5, 6, 7, 8, 9}
print(len(dict))


